Motion-picture camera



1 ,549,34&

Aug. H, 1925.

v c. H. CLARK MOTI N PICTURE CAMERA Filed Jan. 11, 1921 lNVENGR u 7% wkWWfMwZa mmmsw Patented Aug. 11, 1925.

UNITED STATES CHARLES H. CLARK, OF NEW YORK, N.

MOTION-PICTURE CAMERA.

Application filed January 11, 1921. Serial 110. 438,508.

To all whom it may concern:

Be it known that I, CHARLEs H. CLARK, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain IliW and useful Improvements in Motion- PictureCameras, of which the following is a specification.

This is a continuation in part of my ap- .plication Ser. No. 392,969,filed June 30,

This invention relates to motion picture cameras of the ultra-speedtype, and has to do especially with the mechanism for pulling or feedingthe film past the shutter opening, and associated mechanism for1ntermittently stopping and correctly positioning the film strip, andhas-for its chief objects to provide means to pull or feed such film bya rotary mechanism, to so combine the parts that the exact point atwhich th film is released and comes to rest is determined by one or morestops, to so construct the parts that the central portion of the film isfree from frictional contact with metal parts which tend to scratchthe-film and cause static electricity, to prevent buckling of the filmand to guard against rebounding of the film when run at high speeds, allof which objects, among others, are accomplished by the construction,combination and arrangement of parts herein after described and shown byway of example only, it being understood that the invention is capableof embodiment in many oth' r forms not herein shown or specificallydescribed.

In the accompanying drawings:

Figure 1 represents a front elevation of a motion picture camera withthe preferred form of my invention applied thereto;

Figure 2, a sectional view through thefront plate of said camera, on theline 22 of Figure 1, looking in the direction of the arrows, and showingthe driving gears, feed rotor or puller in sid elevation, partiallybroken away and sectioned, and their shafts inend elevation;

Figure 3, a rear elevation of the front plate; v

Figure 4, an enlarged sectional view of the front plate on the line 4-4of Figure .5, looking in the direction of the arrows,

and showing the feed rotor in elevation; F1gure 5, an enlarged sectionalView on 1 as shown.

the line 55 of Figure 4, looking in the direction of the arrows, andshowing an end view of the rotor partially broken away,

and a side elevation of the film stop mechanism; Figure 6, an enlargeddetail sectional .virw taken on the line 66 of Figure 5,

looking in the direction of the arrows, and omitting all parts exceptthe segment plate and a portion of the rotor witha pair of teeth toillustrate the path of travel of said teethwith relation to the ribs ofsaid sector plate;

Figure 7, a side elevation of onset the rotor flanges, broken away, andon a very enlarged scale to show the preferred form of the teeth;

Figure 8, a rear elevation of plate 12;

, Figure 9, a section on the line 9-9 of Figure 8;

Figure 10, an enlarged sectional view, similar to Figure 5, showing amodified form of stop mechanism; and

Figure 11 a greatly enlarged detail View of th end of the stopprojections 52* of the modification illustrated in Figure 10,

Referring now in detail 0 the drawings, 1 designates a section,preferably of metal, of that portion of a motion picture camera framewhich embodies in its construction the shutter opening 11 and mechanismfor drawing the film past said opening, and it is provided withperforated lugs 2 for fastening it to the rest of the camera frame byany usual and suitable fastenings, and is further provided with filmguide ribs 3 preferably made integral with it. A clamp 5 is securedtoplate 1 by any suitable means, such as screws 10, and to this clamp 5is preferably hinged orjournaled the lid or door 4 by means of hinges01' journals 6, this door or lid 4 beilng normally held closed over thefaces of guides 3 by the spring catch 7, which may be mounted, as shown,by screws on one of the brackets 34- which may be made integral with theplate The shutter opening 11 in plate 1 is preferably defined by theedges of an apertured steel plate 12 against which the film 13 rests asit passes the shutter opening 11, said plate preferably being separablefrom the plate 1, and secured to known as X. Back negative to eliminatestatic electricity. This negative has a gumlike substance that gatherson flange 17 and plate 12, causing scratching of the film when run athigh speeds and even at slow speeds occasionally. To eliminate this l.corrugate the face of flange 17 and the .opposing face of plate 12 bycutting shallow groovas in the opposing faces of ,said two parts to formregistering opposed ribs, such grooves being sufiicient in depth and ofsuch number as to permit this substance to freely passthrough saidgrooves without sticking to the face of flange 17 or plate 12.

The lid or door 4 has a shutter opening 15 which registers with shutteropening 11, and a shutter frame, comprising preferably an extensioncollar 16 and a smooth flange 17 with rounded outer edges on its bearingface, is so arranged that its collar fits loosely in shutter opening 15to position said frame, and its flange 17 bears against film 13 andpresses it against plate 12, the flange 17 bemg provided with two screws18 which project through perforations in the door or lid 4 and havetheir heads engaged by leaf springs 21 held respectively between the respective spacing washers 20 and the heads of the respective screws 19,this arrangement providing a delicate floating s ring tension device.This lid or door 4 Wlll be provided with a shutter opening extensionframe 22 surrounding and being flush with the edges of the shutteropening 15, this frame 22 preferably being a separate piece mounted onthe lid or door by any usual means, such as screws 23. Secured to theinner side of the door or lid 4, preferably by any usual means, such asscrews 31, is a plate 30 having a concave recessed segmental inner face,the cord of the segment in which is referably three quarters of an inchin lengt thus corresponding in length to the width dimension of astandard motion picture as now commercially. well known, the, edges ofthe plate 30 being rounded slightly to avoid abrupt bending of the film13 as it enters the segment. The segmental plate 30 is. provided on itsconcaved segmental face with two slightly raised ridges or ribs 24 whichfollow the contour of the segment and are located respectively at theside edges thereof to be in registry with the two lateral rows ofperforations 40 of the well known commercial film 13. .There istherefore no 0 portunity for the bulk of the portion oft e film betweenits two rows of rforations 40 to come into contact with t e plate 30.Also,

the front faces of the ribs 24 are to be s seed at an interval ofapproximately one sixty-fourth of an inch from the periphery of theflanges 38 of the rotor 37 or a very slightly greater interval so thatthe ints of the teeth 39 on said flanges 38 w' just preferably barelyclear said ribs 24, this win allowing ample clearance for, the to nd asit leaves the central part of the segment, while not permitting it tobucklw or to ride off of the teeth 39. A plate 33 is secured to frame 1by any suitable means and provided with bevel ed 5 42, saidedges fittingclosely between the fi l m 13 and the peripheral faces of flanges 38 toact as guides and deflectors for the film strip, the said bevel edgesbeing spaced so as to just clear the points ofthe teeth-39and the outerperipheral faces of the flanges 38. Brackets 34 are rovided withregistering perforations in w ich are preferably arran ed two pairs ofbearings 35 and 43 respectively, the bearings of each pair having acommon axial line, and all of said bearings being secured in saidbrackets 34 by my usual and suitable means. A. shaft 36 is mounted torotate in the bearings 35 and a rotor 37 is firmly secured to said shaftto turn therewith between said brackets 34, and outside of said bracketsa driven wheel 47 is firmly mounted on said shaft 36 to turn therewith.A shaft 44 is mounted in bearings large drive whee 48 mounted thereon toturn therewith and is to have drive connection, which may be h gearteeth, as shown, with the smaller driven wheel 47 on the shaft 36, and adriven wheel 45 is connected to the end of the shaft 44 to turntherewith by any ordinary and usual means, which may be a key 46, and isto be driven by any ordinary and suitable gearing. The rotor 37 has twospaced apart, preferably, though not necessarily, integralannularflanges 38-, the interval between them corresponding approximately tothe interval between the two rows of perforations 40 near the edges ofthe now well known and illustrated commercial film strip 13, and mountedin the periphery of each flange 38 are fourteeth 39 spacedequi-distantly around the said flanges. both flanges being of the samediameter and the teeth of the flanges registering, and all of said teethextending approximately one sixty-fourth of an inch from the peripheralface of their respective flanges, said teeth being longitudinallyarranged in pairs and being placed in the proper longitudinal positionson the flanges 38 to properly mesh into the perforations 40 of thestandard motion picture film 13 above referred to. The operative facesof each of these teeth 39 are formed on an angle sufficiently-great topermit the teeth to freely slide out of the perforations 40. at thepoint of disengagement, but not great enough to cause the teeth to wedgethe film firmly against the face'of the 43 and provided with a segmentin the plate 30 and prevent free j 33, which openings register withlarger,

- sarily, constructed of laminated steel springs has one end secured toframe 1 by screws 26. In thepresent embodiment stop 25 consists of'twosteel springs riveted together, the inner one of which has twoprojections 27 preferably made integral with its free end, saidprojections being adapted to project through close fitting openings 28in plate openings 29 in plate 1. The projections 27 register withperforations 40 in film 13 and are long enough to extend through thefilm 13 and into holes 62 in the ribs 56 of plate or block 57 to causethe film to stop when released from teeth 39 after being pulled therequired distance. In the operation of the stop 25 it is of importancethat the projections 27 shall have come to a full stop before the filmstrikes them, in order that the lateral movement of the stop may notcause the rapidly traveling film to buckle, also, it is importantthatthe projections 27 shall be braced on either side of the film by thewalls ofthe holes or openings 28 and 62 before the film strikes suchprojections 27 in order that said projections may not be bent orotherwise damaged by the fast traveling film. The outer spring of stop25 has a projection 41 on its free end which engages a projection 50 ona block 51 secured to' frame 1 by screws 52 to limit the outwardmovement of the stop 25 and its projections 27. Sufficient movement isallowed projection 41 to permit the projections 27to engage anddisengage the film 13 when the stop 25 is forced in and out by the rotor37 A striking plate 53 is mounted on stop 25 by rivets 54 and is adaptedto be engaged by cam pins 55, which may be integral with the rotor 38.The block 57 is secured to the inner face of plate or door 4 by screws58., sufficient clearance space only being allowed between the ribs 56on block 57 and the plate 33 for the film 13 to freely slide betweenthem. The central portion of the front face of the block 57between itsribs 56 isreoessed or cut away to pre vent its coming into contact withthe film 13.

Ratchet pins '59 are slidably mounted in openings or holes extendingthrough lid or door 4, plate 57' and its ribs 56 and'are in registerwith the openings 40 in film 13, and are so placed and so arranged thatthe .:-beveled ends 60- of said pins 59 will project into erforations 40of film 13 and prevent the lm from rebounding after it strikes againstprojections 27 on stop'25. A spring 61 is secured to the back of lid4'by screw 63, the two free ends of said spring, passing throughopenings 64in ratchet pins 59 andbeing adapted to press the pins 59against of the teeth 39 passing through it.

forations 40 slide past the beveled ends 60 and force 1 the ratchet pins)59- outward against the action of their spring 61.

The rotor is so mounted that the points of the teeth 39 fit very closelyto, but do not touch, the faces of the ribs 24of the seg ment in plate30, which segment is shaped to conform to a circle described by thepoints The distance between the peripheral faces of flanges 38 and theribs 24 of the segment face, being approximately one sixty-fourth of aninch, allows ample clearance for the standard film to pass between suchopposed surfaces without binding and the distance through the segment issuch that the perforations 40 always register with'the edges 32 of plate30 during the exposure period, thus permitting the teeth 39 to freelyenter the perforations regardless of which direction the rotor isrotating in.

The diameter of each flange 38 is approximately two inches in theembodiment illustrated and four teeth 39 are mounted ineach flange andspaced equidistantly from each other, the teeth on the two flanges being in axialali-gnment with each other.

The operation of the embodiment illustrated in Figures 1 to 9 inclusiveis'as follows: the rotation of the gear 45 and gear 48 in a clockwisedirection will serve to rotate gear 47 and rotor 37 in acounterclockwise direction. The teeth 39, which are inmesh withperforations 40 near the facesof the ribs 24 of the segment as the teethpass through said segment, while the clearance between the ends of saidteeth and the faces of said ribs is too'small to allow the film toslip-over the ends of the teeth, and the film thus travels with theteeth through the segment'until the curved edge 32 is reached, where thefilm slips over the end of the tooth and comes to rest for the exposureperiod.

The number of exposures per rotation of the rotor and the relativelength of the periods of exposure and non-exposure will, of course, varyin accordance with the number of teeth or groups of teeth on therespective flanges of the rotor, the period of exposure increasing'inaccordance with the decrease in the number of teeth or groups of teeth.Also, the length of the cord of the segment will, of necessity, vary inaccordance withthe number of teeth in each group, the length of the cordof the segment, where a single tooth to a group is used, beingapproximately three fourths of an inch, where two teeth to the group areused, it will be approximately nine sixteenths of an inch, where threeteeth to the group are used it will be approximately six sixteenths ofan inch, and where four teeth to a group are used it will beapproximately three sixteenths of an inch.

, For most purposes it is desirable to have an ultra speed camera takepictures at a speed of about one hundred and twentyeight pictures persecond and to have as much exposure as possible. In the presentembodiment shown in Figures 1 to 9 inelusive, if the gears 45 and 48 berotated at a speed of eight revolutions per second, which may be easilyaccomplished with any usual and well known gearing the rotor 37 and gear47, which is four times smaller than the gear 48, will make thirty-tworevolutions per second and, since the rotor 37 is provided with fourpairs of teeth 39, the rotor will intermittently feed the film onehundred and twenty-eight times per second.

hen the camera and feed mechanism is operated at anything like the aboverate the speed of feed or travel of the film becomes excessive and it isdifficult to properly control the film, so that it becomes necessary tomake the projections 27 relatively thin so that'they may enter theperforations 410 and come to rest in engagement with the metal walls ofthe perforations or holes 28 and 62 on the respective sides of the filmand so be properly braced and motionless before the film 13 contactswith said projections 27 and has its downward movement thereby stopped.The film strikes the projections 27 with considerable force and, but forthe closely positioned faces of ribs 56 of block 57, would buckle andslide over the ends of the projections 27 and continue on for aconsiderable distance before coming to rest. However, since it' cannotbuckle, and because of the. arrangement above stated, it rebounds unlessmeans to prevent such rebounding are provided. I have, in order toprevent such rebounding, provided the ratchet pins 59 above theprojections 27 these ratchet pins 59 having their ends 60 beveled topermit only downward feeding of the film and bein pressed by theirspring 61 "into the per orations 4110f thefilm 13, are roperly spacedfrom projections 27 so' as to register with a set of perforations 40 ofthe film 13 when the pro jections 27 are positioned in a lower'set ofperforations of said film, so that when the perforations 27 enter thelower set of perforations 40 to prevent downward movement, the ratchetpins 59 enter the upper set of perforations 40, as mentioned and preventrebounding upward'movement, the two sets of stop devices cooperating tohold the' film momentarily motionless and corforce the sto 25 with itsprojections 27 to engage the film 13 immediately after itis disengagedfrom the teeth 39 in its downward movement, and the plate 53 is soshaped and placed that the stop is permitted to disengage the cams andthe film fora considerable periodbefore the next set of teeth 39 enterthe film and pull it downward, makin it possible to use a stop 25 havingbut slight spring tension which will not appreciably retard the speed ofthe rotor, and which will have ample time to disengage itself from thefilm at high speeds of operation of the camera.

However, in case it is not intended to operate the camera at highspeeds, I find that a modified form of stop mechanism may be used withgratifying results, taking the place of the now common spring tensiondevices and thus eliminating much friction. In this modified form,illustrated in Figures'lO and 11, the ratchet ins 59 and their spring 61are dispensed wlth and in place of the projections 27 I substitute theprojections 27 which are made equal in thickness at their bases to thewidth of the perforations 40 of the film 13- and are thus capable ofpositioning the film, when fed in either direction, when forced into itimmediately preceding the exposure period, and have their free endsformed with con verging edges and a blunt tip to ensure free entry ofthe projections into the perforations 40 without damage to the film.Also, in place of the holes 28 in the plate 57 I substitute holes 28',which correspond in size to the size of, and receive, the projections27. The omission of the ratchet pins 59 from this modified form permitsthe feeding of the film in either direction.

Otherwise the construction and operation are the same as in thepreferred form.

In motion picture cameras of any make, friction of the camera mechanismis eliminated as much as possible, as such friction,

especially at high speeds, causes static electricity, makes scratches inthe film and limits the speed at which the film can'be pulled throughthe mechanism without causing damage to the film perforations. In thepresent embodiments all pressure against the film has been eliminatedoutside of the usual small pressure against the aperture plate 12. Thefilm may touch plate 33, but is not pressed against it at any point andas an extra precaution the central portions of block 57 and plate 30have been recessed or cut away to provide an extra clearance for thefilm to freely pass through.

Having thus described my invention, what I claim as new and deslre tosecure by Letters Patent is:

1. In film feeding mechanism for motion picture cameras, a device forintermittently engaging and feeding the film, m combination wit arigidly fixed non-yieldable plate having non-yieldable ribs, the sa1dplate loeing recessed between said ribs to avold contact with the film,and said ribs and means heinglocated on 0 posite sides of the film andregistering with the perforations in said film and with each other andheing located at such distance from each other that, with said means infeeding engagement with the film, the said ribs w ll prevent the filmfrom slipping ofi of sa1d means before the latter have made their fullfeeding movement. I

2. ln film feedin mechanism for motion picture cameras, a evice forintermittently engaging and feeding the film in combination wit havingnon-yieldable ribs, the said plate being recessed between said ribs toavoid contact with the film, said ribs and means being located onopposite sides of the film and registering with the perforations in saidfilm and with each other, and the said device and rihs being so locatedwith respect te each other as to form a narrow throat through which thefilm passes, the said ribs serving as. a hachng to prevent the film fremhecoming prematurely disengaged from said means,

3, In a motion picture camera intended to he used with a film strip havia series of regularly spaced aligned per orations,

means for feeding said film, and positive means for abruptly stoppingthe travel of said film strip in one direction when said stripdisengaged from the feeding means, in comhination with ratchet means inline with said perforations and means for yieldingly pressing saidratchet means toward said film and into said perforations, theintermediate portions of said film between said perforations forcingsaid ratchet means outward ainst the action of said yielding means whenthe film is fed in one direction, but engaging against, and being heldagainst reverse movement loy, said ratchet means d. In a metion picturecamera intended to he used with a film strip havin a series of regularlyspaced aligned perforations, means for intermittently feedin said film,and means actuated hy the feeding means for projecting through one ofsaid perforations to ahruptly stop the travel of said strip, incombination-with spring pressed means, in advance of said stop means, inthe direction of travel of said strip, adapted to engage in one of theperforations of said strip to prevent its rebounding ofi of said stepmeans.

5. In a motion icture' camera intendedto used'with a u strip having aseries a rigidly fixed non-yieldable plate of uniformly spaced alignedperforations, means for intermittently feeding said film strip and meansfor abruptly stopping the travel of said film strip in the direction offeed as it-is disengaged by said feeding means, in combination withmeans for preventing rebounding of the film strip from said stop means,said rebound prevention means comprising a plunger arranged in advanceof said stop means, in the direction of feed of said strip, andresilient means for forcing said plunger toward. said strip and into theperforations thereof, said plunger having its operative end sloping topermit the film strip to force it outward against the action of saidresilient means when the film is fed in one direction.

6. In a motion picture camera intended to be used with a film striphaving a series of regularly spaced'aligned perforations, a feed rotorhaving a tooth, to intermittently engage and feed said strip, andprovided with a cam, in combination with a stop yieldingly held out ofthe path of travel of the film strip and engaged at regularpredetermined intervals by said cam during the rotation of saidrotor toproject through a perforation in the film strip and stop the forwardmovement of the latter as it is disengaged from the tooth of the rotor.

7. In a motion picture camera intended to be used with a film striphaving a series of uniformly spaced perforations, a plate arranged onone side of the film strip, and a block arranged on the opposite side ofthe film strip and provided with a rib, the face of which is arrangedclosely adjacent the plateto prevent buckling of the film,

strip while allowin ample room for the free passage thereo between thefaces of said rib and said plate, and a spring pressed pin workingthrough said rib' to engage in said perforations and having its outerface beveled in order that it may ride over the portions of said filmstrip between the per-. forations when said strip is fed forward, butcannotride over said portions in case the film should try to reboundfrom the stop, in combination with intermittent feed means and a stop.

a 8. In a motion picture camera intended to be used with a film striphavinga series of uniformly spaced aligned perforations, means forintermittently feeding said film strip and means for abruptly stoppingthe travel of the film strip as it is disengaged by the feeding means,in combination with means for reventing rebounding of the film strip romsaid stop means, said rebound prevention means comprising a plunger, andmeans for forcing sa1d plunger and into one of the per-' toward saidstri forations thereo at a point distant lengthwise of said film fromsaid'stop means.

nee

. combination with a said plate and said device being 9. In film feedingmechanism'forfinotion picture cameras, a plate having a segmental ace,in'combination with a rotatably mounted device having a portion forengaging tion picture cameras, a plate having 'a segmental face incombination with a rotatably mounted device having a portion for anagingthe film stri and intermittently ceding it forward, t e said plate andsaid device being arranged respectively on vo posite sides of the lmstrip and so close y adjacent to each other that the thickness ofthe-film stri in the space between them' will determine the exact pointatwhich the film will be en aged a ain by said device.

11-. In 1111 feeding mechanism for motion picture cameras, a rotatablymounted device formed with means for intermittently engaging and feedingthe film, in comblllfllilOlIWlth a rigidly fixed non-yieldable plate,the said plate and said devlce being arra ed respectively on o 'positesides of the fi strip and so 'close y together that the thickness of thefilm in the space between them will'determine the exact point at whichthe film will be engaged by said means. V

12. In a film feeding mechanism for motion picture cameras, a-platehaving a segmental face, in combination with a rotatably mounted devicehavin a tooth for engaging in the rforations of a row of perforations 1nthe film strip and intermittently feedin said stri forward, the saidtooth an row 0 perforations being in registry, the said device and saidplate being located on opposite sides of the film strip and at aninterval from each other slightly less than the length of said toothplus the thickness of the filmstrip, and the operative face of saidtooth being beveled from the forward side of its base, in the directionof rotation of said device, toward its tip, thelface of the tooth beinso inclined that it will tend to force the film strip away from .saidmeans toward said late, the latter reventing the film strip m-ridin ofiosaid toot I v 18. In fi n feeding mechanism for motion picture cameras,a rotatably mounted device-formed with a plurality of s aced means forengaging and feeding the fi in plate having a segmenged on the oppositeside from said device and very talsurface anda of the filmfstrip closetosaid device to hold the film strip .on said device when the latter isoperatively engaging said film stri 14. In film feeding mec anism formotion icture cameras, a plate having a segmental ace, in combinationwith a rotatably mounted device having teeth for engaging in theperforations in the film strip and intermittently feeding it forward,the operative faces of the teeth being forward with beveled faces havinga relatively gradual inclination from a radial line and being of suchdegree that the film will have a tendency to" ride up and off of theirtops, and the said plate and device forming a throat between them forthe passage of the film and being arranged so closely to each other thatthe segmental face of the plate will prevent the film strip from ridingof! of the teeth as they pass through the segment defined by saidsegmental face. 15. n film feedin mechanism for motion picture cameras,a p ate having a segmental face, in combination with a .rotatablymounted device having teeth for engagin in the perforations in the filmstrip an feeding it forward, the operative faces of the teeth beingformed with beveled faces having a' relatively gradual inclination from'a radial line and being of such degree that the film strip will have atendency to ride up and off their tops, and the said plate and deviceforming a throat between them for the passage of the film strip andbeing arranged so closely to each other that the segmental facewillprevent the film strip'from riding off of the teeth as they pass throughthe segment defined by said segmental face, the ends of the segmentalfacev being rounded to avoid too abrupt bending of the film strip.

16. In film feedin mechanism for motion icture cameras, a p ate having asegmental ace, in combination with a rotatably mounted device havingteeth for enga ing in the perforations in the film stri anintermittently feeding it, the o erative faces of the teeth being soformed t at the film strip will have a tendency to ride up off of theirtops, and the said plate anddevice formin a throat between them for thepassage 0 the film strip and being arranged so closel to each other thatthe segmental face rwi prevent the film st'ri from riding off of theteeth as they pass t rough the segment defined by said se ental face,the ends of said segmental ce being rounded, and means on the same sideof the, film as said device I and located. adjacent the rounded ends ofthe segmental face and acting to deflect the film strip from the face ofsaid device and at a tangent thereto.

1.7. In film feeding mechanism for motion picture cameras, a "movablymounted plate having a segmental face, in combination with a rotatably'mounted device having teeth for engaging in the perforations in the filmstrip andintermittently feeding it, the operative" faces of the teethbeing formed with; beveled faces having a relatively gradual inclinationfrom a radial line and being of such degree that the film will have atendency to ride up and ofl'of their tops,

and the said plate and device normally forming a throat between them forthe passage of the film and being arranged (10 closely to .each otherthat the segmental face of the plate will prevent the film strip fromriding off of the teeth as they pass through the segment defined by saidsegmental face,

the said plate being movable away from said feeding device. r

18. In film feeding mechanism for motion picture cameras, a rotatably'mounted device formed with a plurality of teeth spaced at equi-distantintervals of a circle concentric with the axis of said device forintermittently engagirig the film strip and intermittently feeding it,the said teeth each not exceeding one sixty-fourth of an inch from rootto tip.

1 19. In film feeding mechanism for motion picture cameras, a rotatablymounted device formed with a plurality of spaced means for engaging andfeeding the film, in combination with a plate normally held rigid andimmovable with relation to said rotatable device and *arranged on' theopposite side of the film strip from said device and very close to saiddevice to hold the film strip on said device when the latter isoperatively engaging said film strip.

In testimony whereof, I have signed my name to this specification intlie presence of two subscribing witnesses.

cHARLEs H. CLARK. Witnesses H. F. BoNNnL, P. T. REILLY.

